Right now, recycled circuit board coasters are my living line of defense between condensation and the fragile finish of $US 30 coffee tables. (Yes, I spent as much on the coasters as the tables they protect). And even though these coasters really are pretty fantastic, they can be out-gunned during my larger gatherings that feature more condensation.
Needless to say, a coaster afficienado such as myself is consider the purchase of these Pac-Man coasters with box. For $US 22, my crappy furniture never slept so soundly. Here's a bonus pic: